614725 - createElement should do ASCII lowercasing

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Boris Zbarsky [:bzbarsky]]

The relevant code:

  PRBool needsLowercase = IsHTML() && !IsLowercaseASCII(aTagName);
  nsAutoString lcTagName;
  if (needsLowercase) {
    ToLowerCase(aTagName, lcTagName);
  }

Can we just always call the ASCII ToLowerCase on the input string and be done with it?

Comment 1

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

I don't feel strongly, but whatever we do should be put in Web DOM Core.

The IsLowercaseASCII check definitely feels silly.

If we do always lowercase, it'd make sense to me to hook things up to tables which ensures that svg and mathml elements can be created as well.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Oh, by "always" I meant "whenever IsHTML()".  As in, get rid of the IsLowercaseASCII thing, and change the way we do the lowercasing to do ascii-only.

That said, IsLowercaseASCII was added in bug 566466.  Maybe we have performance data indicating it helps?

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

I added IsLowercaseASCII because of performance reasons. We want to avoid
extra allocations and memcopying.
Another option would be to change ToLowerCase so that it doesn't always
effectively memcpy.

Comment 4

[Anne (:annevk)]

http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#dom-document-createelement

Comment 5

[Boris Zbarsky [:bzbarsky]]

This got fixed in bug 492931.